Field of the Invention
This invention relates to medical devices. More particularly, this invention relates to placement and operation of probes within the body of a subject.
Description of the Related Art
When a physician manipulates a catheter during a medical procedure, the catheter may become twisted or tangled. Several methods and systems have been proposed in order to detect or avoid such situations. For example, U.S. Pat. No. 5,921,978, whose disclosure is incorporated herein by reference, describes a catheter that includes fluoroscopic marker components. Some of the disclosed catheter configurations are used for providing visual information to the physician regarding the direction and degree of twist of the catheter distal end.
U.S. Pat. No. 5,352,197, whose disclosure is incorporated herein by reference, describes a turn limiter for a catheter with a twistable tip. The catheter has a flexible wall for use in complex twisting anatomy, and contains a torque wire or a torquable guide wire lumen. The torque wire or torquable guide wire lumen extends through the length of the catheter and is attached to the catheter at or near the distal end thereof. The proximal end of the torque wire protrudes from the proximal end of the catheter and is attached to a turn limiter. The turn limiter allows limited rotation of the proximal end of the torque wire or torquable guide wire lumen without axial dislocation.
U.S. Patent Application Publication No. 2012/0035467, commonly assigned herewith and herein incorporated by reference, describes a catheter entanglement limiter. An operator of an elongated probe manipulates the proximal end of the probe so as to move the distal end within a body of a patient, automatically measuring a cumulative angle of rotation that is applied by the operator to the proximal end. An indication of the cumulative angle of rotation is presented to the operator.